This is my second attempt at an SCP article, the first one was a (literal) train wreck, but I hope this one is a bit better.
Some questions I have for all would-be reviewers:
1) Is the idea interesting?
2) Are some of the Logs/Incidents unnecessary?
3) Do I need to add different addenda (Documents/Interviews)?
4) Is the switch from Safe to Euclid warranted?

Hello, I would say the idea does sound very fun and interesting. While I am new to the site I have two criticisms of my own.
1. You should put how SCP-XXXX-1 replicates SCP-XXXX. It feels very uncreative to just say "the process for this is unknown". Perhaps once SCP-XXXX is ingested the new subjects body will continuously produce the substance within the bone marrow where the blood is made. So then, the way SCP-XXXX-1 can infect other people is by using their own blood (similar to aids).
2. While the fact that SCP-XXXX can spread by air, and SCP-XXXX-1 tries to infect others, I would say make this SCP more dangerous. You don't have to change the object class, just make it pose more of a threat than making people far right. You wrote that this SCP makes people adopt fascist ideologies, I would add on it also makes them more prone to violence; especially discriminatory violence. I would also say give all instances of SCP-XXXX-1 a basic knowledge of each others location. That way SCP-XXXX-1 could gain up in numbers, and then the public would have to worry about an anomalous, intelligent, violent, Nazi-esque, army.
I don't know these were just the first thoughts that appeared in my head, hopes this helps!

You should put how SCP-XXXX-1 replicates SCP-XXXX. It feels very uncreative to just say "the process for this is unknown". Perhaps once SCP-XXXX is ingested the new subjects body will continuously produce the substance within the bone marrow where the blood is made. So then, the way SCP-XXXX-1 can infect other people is by using their own blood (similar to aids).

Th reason I left it with "the process is unknown" and added no way for SCP-XXXX-1 in and of themselves to be infectious is because then it would be much too easily detectable. You could just do a blood test of a potential SCP-XXXX-1 instance and instantly know if they were infected or not. Or just lock them up and wait for them to make some more SCP-XXXX by other means to confirm their status.